sign in sign up
<<
Home , Chukchi Peninsula, Kutnohorite, Magnesite, Sericite

See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/284918589

Quartz-sericite and argillic alterations at the Peschanka Cu-Mo-Au deposit, Chukchi ,

Article in Geology of Deposits · May 2015 DOI: 10.1134/S1075701515030034

CITATIONS READS 6 198

7 authors, including:

Ivan Baksheev A. F. Chitalin Lomonosov Moscow State University INSTITUTE OF GEOTECHNOLOGY LLC, Moscow, Russia

61 PUBLICATIONS 222 CITATIONS 19 PUBLICATIONS 63 CITATIONS

SEE PROFILE SEE PROFILE

Ildar Kalko Vsevolod Yuriyevich Prokof’ev Lomonosov Moscow State University Russian Academy of Sciences

22 PUBLICATIONS 46 CITATIONS 312 PUBLICATIONS 1,133 CITATIONS

SEE PROFILE SEE PROFILE

Some of the authors of this publication are also working on these related projects:

Magma - tectonics - ore events - geology - inclusions RELATION and correlation (in , , Tajikistan etc). etc. View project

Fluid Inclusion Characteristic of the Kisladag Deposit View project

All content following this page was uploaded by Vsevolod Yuriyevich Prokof’ev on 07 December 2015.

The user has requested enhancement of the downloaded file. ISSN 10757015, Geology of Ore Deposits, 2015, Vol. 57, No. 3, pp. 213–225. © Pleiades Publishing, Ltd., 2015. Original Russian Text © L.I. Marushchenko, I.A. Baksheev, E.V. Nagornaya, A.F. Chitalin, Yu.N. Nikolaev, I.A. Kal’ko, V.Yu. Prokofiev, 2015, published in Geologiya Rudnykh Mestorozhdenii, 2015, Vol. 57, No. 3, pp. 239–252.

Quartz–Sericite and Argillic Alterations at the Peschanka Cu–Mo–Au Deposit, Chukchi Peninsula, Russia L. I. Marushchenkoa, I. A. Baksheeva, E. V. Nagornayab, A. F. Chitalinc, Yu. N. Nikolaeva, I. A. Kal’koa, and V. Yu. Prokofievd a Mocow State University, Moscow, 119234 Russia b Vernadsky State Geological Museum, Russian Academy of Sciences, ul. Mokhovaya 11, str. 11, Moscow, 125009 Russia c Regional Company LLC, ul. Sadovnicheskaya 4, Moscow, 115035 Russia d Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry, Russian Academy of Sciences, Staromonetny per. 35, Moscow, 119017 Russia Received July 22, 2014

Abstract—The porphyry Peschanka ––gold deposit and the Nakhodka ore field located in the Baimka ore trend on the western Chukchi Peninsula are spatially related to monzonitic rocks of the Early Cretaceous Egdykgych Complex. Two types of quartz–sericite metasomatic rocks (QSR) have been identified at both the deposits and the ore field: (I) chlorite–quartz– rock with and chal copyrite (porphyry type) and (II) –quartz––muscovite ± phengite rock accompanied by veins with basemetal mineralization (subepithermal or transitional type), as well as carbonate–quartz– rock (argillic alteration) accompanied by veins with precious metal mineralization (epithermal type). The QSR I chlorite evolves from chamosite to clinochlore, which is caused by increasing H2S activity in min eralizing fluid and precipitation of . The QSR I clinochlore is significantly depleted in silica as compared with that from the rocks affected by argillic alteration. The chemical composition of muscovite from both quartz–sericite alterations is similar. The QSR II evolve from through to , which results from the increasing activity of CO2 followed by the decreasing activity of H2S in min eralizing fluid. The Mn content in dolomite is similar to that in beresite (quartz–muscovite–carbonate– metasomatic rock) of the intrusionrelated gold deposits. Illite from argillic alteration is depleted in Al as compared with that of postvolcanic epithermal Au–Ag deposits. However, carbonates from the discussed argillic alteration and Mnrich dolomite are similar to those from quartz–illite rock at postvol canic epithermal Au–Ag deposits. DOI: 10.1134/S1075701515030034

INTRODUCTION Several types of alteration are conventionally iden tified at porphyry copper deposits: biotite–potassium Porphyry deposits are the main source of copper all –quartz (potassic), propylitic, quartz–seric over the world. In Russia, these deposits are located in ite, and argillic. The first type of alteration forms an the , Kuznetsk Alatau, Eastern Syan, Chukotka, internal zone of metasomatic aureole with negligible SikhoteAlin, and Kamchatka folded areas. The larg Cu–Mo mineralization. The outer zone is barren pro est deposits in Russia are Aksug in Tuva and Peschanka pylitic. The quartz–sericite alteration are located in the Chukchi Peninsula; the latter, along with the within the potassic zone and localized above it, Nakhodka ore field (NOF), is situated in the Baimka accompanying the porphyry mineralization. Epither Cu–Mo–Au trend located 200 km south of Bilibino. mal preciousmetal mineralization is spatially related This trend comprises four porphyry copper fields to argillic alteration. In addition, the carbonate–base (from north to south): Yuryakh (YOF), Peschanka metal mineralization frequently developed at por (total copper reserves about 6 Mt) Nakhodka (copper phyry molybdenum–copper deposits (Corbett and reserves about 3 Mt) (Chitalin et al., 2013), and Leach, 1998) is regarded as transitional from porphyry Omchak, which were discovered in the late 1960 to to the epithermal stage. Sillitoe (2010) has proposed early 1970s and were explored up to early 1990s (Migachev, 1984; Migachev et al., 1995; Kaminskii, calling it subepithermal. At most porphyry copper 1989; Shapovalov, 1990; Volchkov, 1982). Prospecting deposits related to granodiorite, this type of and exploration were renewed in 2009 and further ization is spatially related to propylitic alteration. The researches in this were feasible. Mount Milligan deposit in related to monzo nitic rocks exemplifies subepithermal veins and vein Corresponding author: L.I. Marushchenko. Email: lets accompanied by wallrock alteration composed of [email protected] quartz, chlorite, sericite, tourmaline, and carbonates

213 214 MARUSHCHENKO et al.

formed in a continental arc environment. Porphyry deposits are related to the Early Cretaceous Egdykgich Complex, whose monzonitic bodies intrude into the Upper Jurassic volcanic and volcanic–sedimentary sequence (Fig. 1). Nikolaev et al. (in press) have reported in detail the geology of the Baimka trend and separate ore fields and deposits. Bo Four types of altered rocks were identified at the lsh oi deposits and prospects within the Baimka trend: An yu (1) biotite–potassium feldspar–quartz (BPFQR), i R iv er (2) propylite, (3) quartz–sericite (QSR), and (4) argillic. Biotite–potassium feldspar–quartz metasomatic rock forming internal zone of metasomatic aureole is predominant at the Peschanka deposit and prospects of YOF. Propylite occurring at all locations of the I Baimka trend forms an outer zone of hydrothermal alteration replacing intrusive, volcanic, and volcanic– sedimentary rocks. The abundance of quartz–sericite I 1 alteration increases from the YOF to NOF, indicating the decreasing erosion level of ore fields. Quartz– 2 sericite alteration is sporadic in YOF. At the Peschanka II deposit, it forms zones cutting BPFQR, while in NOF 3 it is the most abundant. Carbonate–quartz–ilite metasomatic rock to which epithermal precious metal 4 mineralization of the Vesenny deposit is related is abundant in NOF. Metasomatic rock containing illite 5 III is attributed to argillic alteration (Zharikov et al., 1998). Altered rock with illite was found neither at the 6 Peschanka deposit nor in the YOF. In the Omchak ore field, argillic alteration is represented by calcite–adu IV laria–chlorite rock. The porphyry Cu–Mo mineralization spatially 20 km related to potassic and quartz–sericite zones com prises impregnation and stockworks of quartz veins and veinlets with bornite, , , Fig. 1. Location of ore fields within the Baimka trend. pyrite, and Tifree . The average Cu and Mo (1) Ore field, (2–5) Types of hydrothermal alteration: grades at Peshanka and Nakhodka are 0.53% and (2) potassic, (3) propylitic, (4) quartz–sericite zones cut ting potassic alteration, (5) argillic. (I) Yuryakh, 140 g/t and 0.34% and 54 g/t, respectively (Chitalin (II) Peschanka, (III) Nakhodka, (IV) Omchak. et al., 2013). The Re/Os model age of molybdenite from the Peschanka deposit and NOF is 142.6 ± 6.9 and (Le Fort et al., 2011). Similar metasomatic rock 143.3 ± 3.0 Ma, respectively (Baksheev et al., 2014), accompanied by veins with , , and which is proximate, within error, to the U/Pb age of chalcopyrite was found at the Peschanka deposit and the Egdykgych Complex 139.5 ± 0.5 – 140.3 ± 0.5 Ma NOF, but within intrusions. At the Vesenny deposit in (Kotova et al., 2012). The minerals of the carbonate– NOF, quartz–carbonate veins with precious metal basemetal assemblage fill veins and veinlets hosted in mineralization are hosted in quartz–illite alteration both potassic and quartz–sericite alterations. Galena containing Mnrich carbonates. and sphalerite are the major ore minerals; chalcopyrite The objective of this study is to specify the mineral and tennantite–tetrahedrite are minor; enargite, Te ogical features of quartz–sericite alteration related to minerals (hessite, native tellurium), and native gold porphyry and subepithermal mineralization and to are occasional. Economic epithermal mineralization show a difference in argillic alteration at porphyry and spatially related to carbonate–quartz–illite altered postvolcanic epithermal Au–Ag deposits. rock was found at the Vesenny deposit in the southern NOF, with average grade as follows: 2.9 g/t Au, 56 g/t Ag, 0.9% Pb + Zn, and 0.15% Cu. The ore consists of BRIEF GEOLOGY, ALTERATIONS AND Asrich pyrite (up to 10 wt % As), sphalerite, galena, chal The Baimka trend is a part of the Oloi metallogenic copyrite, Znrich tennantite to Agbearing (4 wt % Ag) zone, where Cu–Mo–Au porphyry systems were Znrich tetrahedrite, lowfineness native gold, elec

GEOLOGY OF ORE DEPOSITS Vol. 57 No. 3 2015 QUARTZ–SERICITE AND ARGILLIC ALTERATIONS 215 trum, and hessite; petzite, stützite, pearceite, and RESULTS are rare. Low fineness gold (756–857) and Quartz–sericite altered rocks are light gray, whitish electrum (657–743) enclosing and filling fractures in with lepidogranoblastic and relict porphyritic textures; pyrite, galena, and tennantite–tetrahedrite are inti their structure is massive. Muscovite, phengite, and mately intergrown with hessite and petzite. quartz are the major rockforming minerals; chlorite, albite, tourmaline and carbonates are minor constitu In the Omchak ore field, epithermal Ag mineral ents. Rockforming minerals of replaced magmatic or ization, represented by naumannite, Serich pearceite metasomatic rocks remained at weak hydrothermal (up to 4 wt % Se), and acanthite, was found along with alteration: potassium feldspar, plagioclase, biotite, and ordinary porphyry molybdenum–copper mineraliza magnetite. Rutile and apatite are accessory minerals of tion. In addition, rare algodonite was identified quartz–sericite metasomatic rocks. Quartz–sericite (Nikolaev et al., in press). rocks are divided into two types in mineralogy: (I) chlorite–quartz–muscovite rock (QSR I) with bornite and chalcopyrite (porphyry type) and (II) tourma ANALYTICAL METHODS line–quartzcarbonate–muscovite ± phengite rock (QSR II) accompanying veins with basemetal miner Electron microscopic study of rockforming min alization (subepithermal or transitional type). Car erals and the determination of their chemical compo bonate–quartz–illite argillic rock is light gray, fine sition were performed with a Jeol JSM6480LV SEM grained, and massive. This rock is composed of illite, equipped with an INCAEnergy 350 EDS and INCA Mnrich dolomite, rhodochrosite, quartz, rare chlo Wave 500 WDS at the Laboratory of high spatial reso rite, and relict albite and sericite. lution analytical techniques, Division of Petrology, Vertical zoning at the Nakhodka and Pryamoi pros Moscow State University. Backscattered electron pects in NOF is remarked: metasomatic rocks with illite images were obtained at an accelerating voltage of at the upper level grade to QSR I and QSR II at a depth 20 kV and a current intensity of about 2 nA. The of 100–200 m. At the Vesenny deposit in NOF, chemical composition of minerals was measured with ate–quartzillite argillic alteration develops down to 300 m EDS at an accelerating voltage of 20 kV and current below the surface. Argillic alteration is found also at the intensity of 2 ± 0.05 nA. The content of F in tourma flanks of the Vesenny III prospect in NOF. line and was measured with WDS (TAP ) Chlorites of chlorite–quartz–muscovite rock stud at an accelerating voltage of 20 kV and current inten ied here are fine split flakes up to 40 μm in size and sity of about 23 nA using MgF2 as reference material. coarselamellar aggregates up to 300 μm in size. Chlo Stoichiometric and silicates with measured rites replace magmatic biotite, amphiboles, compositions were used as standards for other ele pyroxenes, and phlogopite of BPFQR. ments. We used XPPsoftware for the correction pro Electron microscopy revealed zoning in chlorite cedures (INCA, version 15a, Oxford Instrument). The grains. A backscattered electron image (Fig. 2a) uncertainty of single measurement does not exceed shows that the darker rims of chlorite lamellae 1.5% relative. depleted in Fe are close to sulfide minerals, whereas the lighter cores are enriched in Fe; chlorites enriched Tourmaline formulae were normalized on the basis in Fe occur also in barren altered rocks. It is probable of 15 cations, excluding Na, Ca, and K, i.e., assuming that chlorite enriched in Fe predates that depleted in no vacancies at the tetrahedral or octahedral sites, and Fe; the latter crystallized when sulfide minerals pre an insignificant content of Li (Henry et al., 2011). cipitated. Chargebalance constraints were used to estimate the According to the classification of Bailey (1980), the amounts of OH– and O2– associated with the V and W chlorites studied here are categorized as chamosite anion sites in the structural formula. The proportion of and clinochlore (Table 1, Fig. 3). In general, chlorites Xsite vacancies () was calculated using stoichiomet of the Peschanka deposit are depleted in silica as com ric constraints by means of 1 – (Na + Ca + K). The pared with those of NOF. The clinochlore and cha amount of B2O3 was calculated from stoichiometric mosite of the Peschanka deposit are enriched in Mn constraints. Fe2+/Fe3+ ratio was calculated from (0.19 and 0.12 apfu, respectively) as compared with chargebalance constraints. The formulae of chlorite those from NOF (0.06 and 0.03 apfu, respectively). and sericite were normalized on the basis of 10 cations The concentration of other trace elements in chlorite and 22 anions, respectively. The H2O content in these does not exceed a few hundredths apfu. minerals was calculated from stoichiometric con Chlorite from argillic rocks of NOF is fine (up to straints. The crystal chemical formulae of the dolo 10 μm) flakes of clinochlore having a higher Si content mite and calcite group minerals were calculated on the (3.58 apfu) than that of QSR I (2.87–3.03 apfu Si); basis of 2 and 1 metal atoms, respectively. Average con Mn content does not exceed a few hundredths apfu. tents as atoms per formula unit (apfu) or wt % in the White micas are muscovite, phengite, and illite. discussed minerals are given below. Muscovite and illite are fineflake split aggregates of

GEOLOGY OF ORE DEPOSITS Vol. 57 No. 3 2015 216 MARUSHCHENKO et al.

Table 1. Chemical composition (wt %) of the minerals from quartz–sericite altered rocks at the Peschanka deposit and in the Nakhodka ore field 123 Component clinochlore chamosite clinochlore chamosite clinochlore (n = 22) (n = 6) (n = 39) (n = 5) (n = 6)

SiO2 27.82 26.91 29.50 26.64 34.59 TiO2 0.02 0.13 0.06 0.08 0.03 Al2O3 19.95 20.93 18.67 19.60 15.49 FeO 20.19 28.03 17.87 28.11 15.21 MnO 2.10 1.33 0.69 0.33 0.18 MgO 17.69 10.59 20.26 12.99 20.74 CaO 0.13 0.11 0.13 0.06 0.66 Na2O 0.24 0.26 0.22 0.13 0.24 H2O 11.34 10.71 11.36 10.95 11.95 F b.d.l. b.d.l. 0.02 0.07 b.d.l. 2F=O 0.01 0.03 Total 99.48 99.00 98.77 98.93 99.09 Coefficients in crystal chemical formulae Si 2.887 2.931 3.033 2.866 3.580 AlT 1.113 1.069 0.967 1.134 0.420 Total T 4.000 4.000 4.000 4.000 4.000 AlA 1.326 1.627 1.294 1.351 1.468 Fe 1.752 2.563 1.537 2.529 1.316 Mg 2.736 1.677 3.104 2.083 3.198 Ti 0.001 0.010 0.005 0.007 0.002 Mn 0.185 0.123 0.060 0.030 0.016 Ca 0.015 0.013 0.014 0.007 0.073 Na 0.047 0.055 0.044 0.028 0.049 Total A 6.062 6.068 6.058 6.035 6.122 F 0.007 0.024 0.000 OH– 7.854 7.670 7.796 7.864 7.353 O2– 0.146 0.330 0.204 0.136 0.324 Fetot/(Fetot+ Mg) 0.39 0.62 0.33 0.55 0.29 (1) QSR I of the Peschanka deposit, (2, 3) Nakhodka ore field: (2) QSR I, (3) QSR II. Here and after, b.d.l. denotes that the content of element is below detection and n is number of analyses.

20–30 μm in size and euhedral lamellae up to 100 μm K2O. The concentration of trace Na, Ti, and Ca does in size. In chlorite–quartz–muscovite rock, muscovite not exceed a few hundredths apfu. and phengite are intimately intergrown with albite or Tourmaline at the Peschanka deposit and NOF replace earlier chlorite and potassium feldspar (Fig. 2c). found from the second type of quartz–sericite rock is from QSR II is intergrown with dolomite and associated with basemetal . The mineral is tourmaline (Fig. 2d). Illite from argillic alteration locally common and occurs as both light green irregu occurs as fine flakes up to a few tens of microns and larshaped isolated grains up to 50 μm in size (Fig. 2b) aggregates of these flakes. and radial aggregates up to 300 μm in diameter (Fig. 2d). The chemical composition of muscovite from both Electron microscopy revealed three generations of types of quartz–sericite alteration of the Peschanka tourmaline from radial aggregates at the Peschanka deposit and NOF is identical (Table 2). The mineral con deposit. Tourmaline of the first generation occurs as tains few Na up to 0.07 apfu and Ti up to 0.02 apfu; the inhomogeneous resulting from a variable con Fetot/(Fetot + Mg) value ranges from 0.38 to 0.41. Pheng tent of Fe and Al. Average contents of Fe, Al, and Mg ite of both types of quartz–sericite rocks at the Pes are 1.56, 5.77, and 1.60 apfu, respectively; the average chanka deposit is richer in Fe (Fetot/(Fetot + Mg) = 0.50), Xsite vacancy proportion is 0.11 apfu (Table 3). The Na (0.04 apfu) and Ti (up to 0.02 apfu), than that in second generation of tourmaline overgrows tourma NOF (0.21, 0.01 apfu, and 0.01 apfu, respectively). line I (Fig. 2d) and forms proper grains. Cores of the Argillic illite is richer in Si (up to 3.31 apfu) than tourmaline II grains are depleted in Fe (a few wt %) as muscovite and phengite. The K content in the mineral compared with the rims (up to 11 wt %). Average Fe decreases toward the flake rims from 9.17 to 8.03 wt % content in tourmaline II 0.85 apfu is slightly lower

GEOLOGY OF ORE DEPOSITS Vol. 57 No. 3 2015 QUARTZ–SERICITE AND ARGILLIC ALTERATIONS 217

(a) (b)

TurII TurIII Ccp

Chl TurI Ab

200 µm 200 µm

(c) (d)

Kfs Ms

Chl Q Chl Tur

Dol

Ms Rt

Kfs Ab 100 µm 50 µm

(e) (f)

Cal Rhd

Sdr

Dol Dol

50 µm 100 µm

Fig. 2. Backscattered electron images of minerals from altered rocks of the Peschanka deposit and Nakhodka ore field. (a) Zoned chlorite flakes intergrown with chalcopyrite in quartz–albite matrix, (b) first, second and third tourmaline generations, (c) oscil latory zoned dolomite crystals associated with weakly zoned tourmaline in muscovite aggregates, (c) muscovite replacing chlorite and potassic feldspar in quartz–albite matrix (d) dolomite overgrew calcite and is replaced by siderite, (e) rhodochrosite overgrew Mnrich dolomite. (Ab) Abite, (Cal) calcite, (Ccp) chalcopyrite, (Chl) chlorite, (Dol) dolomite, (Kfs) potassium feldspar, (Ms) muscovite, (Q) quartz, (Rhd) rhodochrosite, (Rt) rutile, (Sdr) siderite, (Tur) tourmaline.

GEOLOGY OF ORE DEPOSITS Vol. 57 No. 3 2015 218 MARUSHCHENKO et al.

Ftot/(Ftot + Mg) crystals and aggregates of crystals, pockets, and vein 0.7 lets. The isolated crystals reach a few hundred microns in size. Microscopic observation revealed that the ear liest calcite is overgrown by later dolomite and/or magnesite. Siderite replacing dolomite and magnesite 0.6 Chamosite is the latest (Fig. 2e). Carbonates of argillic alteration are calcite, dolo mite, and rhodochrosite. These minerals together with 0.5 quartz, sphalerite, galena, fahlores, hessite, and native 1 gold fill veinlets and pockets. The earliest calcite is fol 2 lowed by rhodochrosite overgrown by Mnrich dolo 0.4 3 mite. Calcite from tourmaline–quartz–carbonate–mus Clinochlore covite ± phengite rock overgrowing feldspar occurs as 0.3 isolated crystals and aggregates of the crystals in argil lic alteration. The QSR II calcite at the Peschanka deposit is richer in Fe (Fe/(Fe +Mg) = 0.77) than that in NOF (0.33). In the both cases, Mn content does not 0.2 2.6 2.8 3.0 3.2 3.4 3.6 3.8 exceed a few hundredths apfu. The Fetot/(Fetot +Mg) Si apfu. value and Mn content in calcite from the rocks affected by argillic alteration is 0.43 and 0.4 apfu, Fig. 3 Classification diagram (Bailey, 1980) of chlorites respectively. from altered rocks of the Peschanka deposit and Nakhodka The dolomite of QSR II intimately intergrown with ore field. (1) Peschanka deposit, QSR I, (2, 3) Nakhodka ore field: (2) QSR I, (3) argillic rock. sericite, quartz, and tourmaline is irregularshaped zoned crystals. The zoning is caused by the variable Fe content. The QSR II dolomite at the Peschanka than that in tourmaline I. The Al and Mg concentra deposit and NOF is characterized by a close Fe/(Fe + tions are 6.28 and 1.95 apfu, respectively; Xsite Mg) value (0.29 and 0.20, respectively) and low Mn vacancy proportion is 0.15 apfu. Tourmaline of the content, up to a few hundredths of apfu. third generation contains 6.3 apfu Al and 1.10 apfu Fe; Dolomite from argillic alteration overgrows and the average Mg concentration is 1.76 apfu; the average replaces rhodochrosite (Fig. 2f) and fill pockets and Xsite vacancy proportion is 0.18 apfu. Ti and Ca con veinlets in metasomatic rock. In contrast to dolomite tent does not exceed a few tenths apfu through the from QSR II, the zoning of dolomite crystals is caused three generations. by alternation of zones enriched and depleted in Mn. Two generations of tourmaline are found in NOF. Average Fe and Mn content in dolomite is 0.18 and Tourmaline of the first generation occurs as large 0.15 apfu, respectively. aggregates composed of fine misoriented weakly Magnesite established only in QSR II of NOF zoned crystals. Average Fe, Mg, and Al contents are occurs as irregularshaped grains. It appeared to crys 1.11, 1.76, and 6.91 apfu, respectively; the average tallize close to dolomite. The Mn and Ca content in Xsite vacancy proportion is 0.16 apfu. The second the mineral is 0.01 apfu. generation of tourmaline occurs as overgrowth rims on Siderite was found in QSR II at both Peschanka and tourmaline I and isolated unzoned crystals up to a few NOF. It overgrows earlier carbonates: dolomite at Pes ten microns in length. The contents of Fe (0.77 apfu), hanka, and dolomite and magnesite in NOF. The min Mg (1.64 apfu), and Al (6.59 apfu) is lower in tourma eral is enriched in Mg (up to 0.3 apfu); the Ca and Mn line II than those in tourmaline I. Xsite vacancy pro contents are negligible. portion is 0.16 apfu. As with tourmaline from the Rhodochrosite was identified in argillic alteration of Peschanka deposit, the Ca and Ti content in the NOF NOF. It occurs as euhedral crystals up to a few mm in tourmaline is a few tenths of apfu. size, which are replaced by Mnrich dolomite. The The compositions of from quartz– mineral has insignificant Mn and Ca admixture, up to sericite altered rocks of the Peschanka deposit and 0.03 apfu. NOF are below the schorl–dravite join and parallel to the AlO(FeOH)–1 exchange vector (Fig. 4a). DISCUSSION The tourmalines studied here are classified as drav The rockforming constituents of quartz–sericite ite and oxydravite according to Henry et al. (2011). rocks at the Peschanka deposit and NOF (micas, chlo Carbonates were identified in QSR II and argillic rite, tourmaline, and carbonates) contain a significant alteration. The QSR II carbonates, calcite, siderite, amount of Mg, which is caused by the replacement of magnesite, and dolomite (Table 4), occur as isolated rocks with minerals enriched in Mg. In the case of

GEOLOGY OF ORE DEPOSITS Vol. 57 No. 3 2015 QUARTZ–SERICITE AND ARGILLIC ALTERATIONS 219

Table 2. Average chemical composition (wt %) of white micas from altered rocks of the Peschanka deposit and Nakhodka ore field

12345

Component muscovite phengite muscovite phengite muscovite muscovite illite phengite (n = 16) (n = 2) (n = 17) (n = 7) (n = 10) (n = 12) (n = 47)

SiO2 47.05 48.95 46.67 49.31 47.36 49.97 45.67 50.25

TiO2 0.32 0.26 0.28 0.30 0.24 0.07 0.35 0.11

V2O3 b.d.l. b.d.l. b.d.l. b.d.l. 0.13 0.16 0.04 0.11

Al2O3 32.96 29.04 32.39 30.63 32.63 31.27 34.57 31.49

FeOtot 2.14 3.91 2.87 2.62 2.28 1.06 1.97 1.54 MnO b.d.l. b.d.l. 0.04 0.07 b.d.l. 0.03 0.02 0.04 MgO 1.98 2.18 2.10 2.00 1.94 2.30 1.59 2.18 CaO 0.01 0.05 0.03 0.04 0.07 0.22 0.05 0.19

K2O 10.12 10.53 10.44 10.29 10.14 9.83 10.05 9.07

Na2O 0.45 0.29 0.37 0.15 0.30 0.07 0.52 0.13

H2O 4.48 4.44 4.46 4.5 4.43 4.53 4.36 4.54 F b.d.l. b.d.l. b.d.l. b.d.l. 0.11 b.d.l. 0.22 0.14 2F=O 0.05 0.06 0.05 Total 99.52 99.64 99.64 99.91 99.69 99.51 99.46 99.82 Coefficients in crystal chemical formulae Si 3.146 3.300 3.138 3.283 3.166 3.303 3.063 3.307 AlT 0.854 0.700 0.862 0.717 0.834 0.697 0.937 0.693 Total T 4.000 4.000 4.000 4.000 4.000 4.000 4.000 4.000 AlM 1.744 1.606 1.703 1.687 1.736 1.738 1.796 1.750 Mg 0.197 0.219 0.210 0.199 0.194 0.226 0.158 0.213

Fetot 0.120 0.220 0.161 0.146 0.127 0.059 0.111 0.085 Mn 0.002 0.004 0.002 0.001 0.002 Ti 0.016 0.013 0.014 0.015 0.012 0.003 0.017 0.005 V 0.007 0.008 0.002 0.006 Total M 2.077 2.058 2.090 2.051 2.076 2.036 2.085 2.061 Ca 0.001 0.003 0.002 0.003 0.005 0.016 0.003 0.013 Na 0.058 0.038 0.049 0.020 0.039 0.010 0.068 0.017 K 0.863 0.905 0.895 0.874 0.865 0.829 0.860 0.761 Total I 0.922 0.946 0.946 0.897 0.909 0.855 0.931 0.791 OH– 2.000 2.000 2.000 2.000 1.976 2.000 1.953 1.994 F0.0240.0470.006 Total A 2.000 2.000 2.000 2.000 2.000 2.000 2.000 2.000

Altot 2.597 2.307 2.566 2.404 2.570 2.436 2.733 2.443

Fetot/(Fetot + Mg) 0.38 0.50 0.43 0.42 0.40 0.21 0.41 0.29 (1, 2) Peschanka deposit: (1) QSR I, (2) QSR II; (3–5) Nakhodka ore field: (3) QSR I, (4) QSR II, (5) argillic alteration.

GEOLOGY OF ORE DEPOSITS Vol. 57 No. 3 2015 220 MARUSHCHENKO et al.

Table 3. Average chemical composition (wt %) of the tourmaline group minerals from the second type of quartzsericite altered rock of the Peschanka deposit and in the Nakhodka ore field 12 Component tourmalineI tourmalineII tourmalineIII tourmalineI tourmalineII (n = 5) (n = 14) (n = 18) (n = 12) (n = 7)

B2O3 10.32 10.50 10.76 10.59 10.61 SiO2 35.10 35.21 35.71 35.88 36.27 TiO2 0.97 0.82 0.26 0.30 0.40 Al2O3 28.98 32.30 32.38 32.10 34.13 FeO 11.07 6.21 7.26 7.91 5.62 MgO 6.37 7.91 7.16 7.14 6.73 CaO 0.77 0.62 0.45 0.10 0.19

K2O 0.03 0.03 b.d.l. 0.02 0.39 Na2O 2.27 2.30 2.31 2.61 2.50 H2O 3.53 3.50 3.46 3.56 3.26 F b.d.l. b.d.l. 0.04 b.d.l. b.d.l. 2F=O 0.02 Total 99.42 99.39 99.80 100.21 100.08 Coefficients in crystal chemical formulae B 3.000 3.000 3.000 3.000 3.000 Si 5.934 5.812 5.899 5.903 5.944 TAl 0.066 0.188 0.101 0.097 0.056 Total T 6.000 6.000 6.000 6.000 6.000 ZAl 5.708 6.000 6.000 6.000 6.000 ZFe3+ 0.081 ZMg 0.211 Total Z 6.000 6.000 6.000 6.000 6.000 AlY 0.000 0.096 0.202 0.125 0.536 Mg 1.393 1.945 1.762 1.750 1.645 Fe2+ 1.483 0.857 1.003 1.063 0.771 YFe3+ 0.025 Ti 0.123 0.102 0.032 0.037 0.049 Total Y 2.999 3.000 2.999 3.000 3.001 Na 0.745 0.735 0.741 0.834 0.793 X 0.108 0.149 0.181 0.144 0.093 Ca 0.140 0.109 0.079 0.017 0.033 K 0.007 0.007 0.005 0.081 Total X 1.000 1.000 1.000 1.000 1.000 OHV 3.000 3.000 3.000 3.000 3.000 OHW 1.000 0.930 0.916 1.000 0.482 OW 0.000 0.070 0.063 0.000 0.518 F0.021 Total W 1.000 1.000 1.000 1.000 1.000

Fetot/(Fetot + Mg) 0.49 0.31 0.36 0.38 0.32 X /(X + Na) 0.13 0.17 0.20 0.15 0.10

Altot 5.774 6.284 6.304 6.223 6.083 Fetot 1.565 0.857 1.003 1.088 0.771 (1) Peschanka deposit, (2) Nakhodka ore field. X denotes Xsite vacancy.

GEOLOGY OF ORE DEPOSITS Vol. 57 No. 3 2015 QUARTZ–SERICITE AND ARGILLIC ALTERATIONS 221

(a) I II III

FeAl–1 3 Schorl Schorl Schorl Al(NaMg)–1

2 Oxyschorl Oxyschorl Oxyschorl Foitite Foitite Foitite MgFe–1

Fe apfu AlO(FeOH)–1 "Oxy "Oxy "Oxy 1 foitite" foitite" foitite"

"Oxymagnesiofoitite" Dravite "Oxymagnesiofoitite" Dravite "Oxymagnesiofoitite" Dravite 10 2 3 10 2 3 10 332 "Oxydravite" "Oxydravite" "Oxydravite" Magnesiofoitite Magnesiofoitite Magnesiofoitite Mg apfu Mg apfu Mg apfu (b) IIIIII Ca Ca Ca

Calcic Calcic Calcic group group group

Alkali Alkali Alkali Xvacant group Xvacant group Xvacant group group group group Xsite vacancy Na + K Xsite vacancy Na + K Xsite vacancy Na + K

123456

Fig. 4. Variations in the composition of tourmaline supergroup minerals from quartz–sericite rocks of (I) the Peschanka deposit, (II) Nakhodka ore field, and (III) Olkhovka deposit, Chukchi Peninsula. (a) Fe versus Mg diagram, (b) Xsite vacancy–Ca– (Na+K) classification diagram (Henry et al., 2011). (1–3) Peschanka deposit: (1) generation I, (2) generation II, (3) generation III; (4, 5) Nakhodka ore field: (4) generation I, (5) generation II; (6) Olkhovka deposit, Chukchi Peninsula. magmatic rocks, these are biotite, diopside, and mag White micas of porphyry copper deposits are nesiohastingsite. In the case of biotite–potasium feld reported in many publications (Sotnikov et al., 2002; spar–quartz altered rock, this is biotite. Mgrich min AlvaJimenez et al., 2011; Dilles et al., 2012). White erals of replaced propytlite are chlorite and tremolite– micas are rockforming constituents of metasomatic actinolite. The major mineralogical features of altered rocks at intrusionrelated and postvolcanic epithermal rocks are given in Table 5. gold deposits. An Al versus Si diagram was constructed to compare the chemical composition of white micas Clinochlore and chamosite of chlorite–quartz– from various types of altered rocks in the Baimka trend muscovite rock are similar in chemical composition to and other types of ore deposits (Fig. 5). The composi those of quartz–sericite rocks reported at the other tions of white micas from QSR I and QSR II fall into porphyry copper deposits (Dilles et al., 2012). The the field of porphyry copper quartz–sericite rocks and compositional evolution of the QSR I chlorites from the field of white micas typical of alteration at pluto nogenic gold deposits. Illite from postvolcanic epith early chamosite to late clinochlore is caused by the ermal deposits is richer in Al (Dilles et al., 2012). The increasing activity of H2S in mineralizing fluids result compositions of illite from carbonate–quartz–illite ing in the precipitation of sulfide minerals with pre altered rock in the Baimka trend fall into the overlap dominant incorporation of Fe into the latter. Cli area of these fields and the field of porphyry copper nochlore of argillic alteration differs from that in QSR I illite. Thus, the composition of illite allows distin in elevated Si content and lower Al concentration. Cli guishing argillic alteration related to porphyry and nochlore with a high Si content is typical of argillic postvolcanic epithermal systems. alteration of geothermal systems (MartinezSerrano At the Peschanka deposit and NOF, tourmaline was and Dubois, 1998). found only from QSR II. However, Rogacheva and

GEOLOGY OF ORE DEPOSITS Vol. 57 No. 3 2015 222 MARUSHCHENKO et al.

Table 4. Average chemical composition (wt %) of carbonates from altered rocks of the Peschanka deposit and Nakhodka ore field

123 Component calcite dolomite siderite calcite dolomite magnesite siderite calcite rhodoch dolomite (n = 13) (n = 20) (n = 6) (n = 7) (n = 40) (n = 3) (n = 5) (n = 11) rosite (n = 23)

CaO 52.35 29.01 1.55 55.02 28.84 0.22 1.23 51.99 1.58 29.82 MgO 0.30 13.93 6.25 0.44 16.04 25.23 11.48 0.77 1.03 12.32 FeO 0.60 9.78 48.93 0.39 6.95 27.62 45.29 1.03 í.ï.î. 6.50 MnO 2.24 0.76 2.43 1.08 0.50 0.37 0.26 2.97 59.19 5.20 Total 55.49 53.48 59.16 56.93 52.33 53.44 58.26 56.76 61.80 53.84 Coefficients in crystal chemical formulae Ca 0.952 1.025 0.031 0.968 1.012 0.004 0.023 0.924 0.032 1.062 Mg 0.008 0.682 0.171 0.011 0.783 0.614 0.302 0.019 0.029 0.608 Fe 0.009 0.271 0.760 0.005 0.190 0.377 0.670 0.014 – 0.181 Mn 0.032 0.021 0.039 0.015 0.014 0.005 0.004 0.043 0.939 0.147

Fetot/(Fetot+ Mg) 0.76 0.28 0.81 0.33 0.2 0.38 0.69 0.43 – 0.23 (1) Peschanka deposit, QSR I; (2, 3) Nakhodka ore field: (2) QSR II, (3) argillic alteration.

Baksheev (2010) reported that at porphyry copper chrosite by dolomite in argillic alteration indicates an deposits tourmaline also occurs in carbonatefree quartz– increasing pH value of the mineralforming solution. chlorite–muscovite alteration accompanying porphyry High Mn concentration in argillic carbonates of NOF mineralization. The triangular diagram (Fig. 4b) shows is also typical of carbonates from quartz–illite alter that tourmaline from carbonatefree quartz–chlo ation and related veins at postvolcanic epithermal Au– rite–muscovite rock is characterized by a much higher Ag deposits (Leroy et al., 2000; Spiridonov, 1992). Ca content than that from the alteration studied here. Therefore, argillic alteration in NOF and related ore is A substantial difference in Ca content is caused by the regarded as epithermal, but is spatially related to the incorporation of this element into carbonates associ intrusive body. ated with tourmaline at Peschanka and NOF, rather than into . At the same time, chemical substitution YAl + WO → YFe2+ + WOH remains (Fig. 4a). CONCLUSIONS Thus, the tourmaline from quartz–sericite alteration The data obtained indicate that two types of accompanying subepithermal basemetal mineraliza quartz–sericite alteration occur at porphyry copper tion is characterized by low Ca content as compared deposits, which accompany porphyry and basemetal with that of QS alteration related to porphyry mineral (subepithermal) ores. These types differ in: (1) chlo ization. rite in QSR I accompanying porphyry ore and carbon ate in QSR II accompanying basemetal ore and (2) The chemical composition of dolomite from tour enrichment and depletion of dravite and oxydravite maline–quartz–carbonate–muscovite alteration of from QSR I and QSR II in Ca, respectively. the Peschanka deposit and NOF is similar to that from Argillic alteration differs from quartz–sericite beresite (carbonate–muscovite–quartz–pyrite alter alteration in the presence of illite and enrichment of ation) at intrusionrelated gold deposits (Baksheev chlorite in silica. In addition, rhodochrosite and Mn and Spiridonov, 1998; Generalov, 1990). In the both rich dolomite develop in argillic alteration. cases, dolomite is characterized by a low content of the kutnahorite end member (Fig. 6a). Illite from argillic alteration in porphyry systems is depleted in Al as compared with that from postvolca The compositional evolution of carbonates in QSR II nic epithermal Au–Ag deposits. from calcite through dolomite to siderite results from the increasing activity of CO2 in fluid (calcite to dolo mite) (Martynov, 1991) followed by the decreasing ACKNOWLEDGMENTS activity of H2S (dolomite to siderite). According to We thank A.I. Brusnitsyn and S.F. Vinokurov, Corbett and Leach (1998), the replacement of rhodo whose constructive comments have significantly

GEOLOGY OF ORE DEPOSITS Vol. 57 No. 3 2015 QUARTZ–SERICITE AND ARGILLIC ALTERATIONS 223 , , (Mn

, magnesite , dolomite dolomite Rhodochrosite Calcite (Mn up to 0.02 apfu) up to 0.09–0.48 apfu) calcite

dravite , oxy (Ca up to 0.16 apfu) Dravite (3.26– (3.29–3.30 apfu, (2.99–3.17 apfu, (2.80–3.03 apfu, 0.21–0.50) 0.12–0.49) 0.26–0.47), (3.08–3.43 apfu, Chemical composition of minerals Chemical composition 3.30 apfu, 0.24–0.49) Illite pahengite Muscovite Muscovite 0.27–0.47), phengite

(2.72–3.05 + Mg) 0.26– tot (Si 2.80–3.12 ap chlorites micas white tourmaline carbonates Clinochlore /(Fe tion of the Peschanka deposit of Nakhodka ore field tion of the Peschanka tot apfu, 0.53–0.69); (Si 3.24–3.62 apfu) fu; Fe 0.47), chamosite Clinochlore ,

, , , tellu galena native

, , chalcopyrite fahlores tourmaline , carbonates , , , , Au–Ag quartz arsenopyrite , electrum , , chalcopyrite bornite

hessite rides , sphalerite chlorite, white micas, quartz white micas white micas gold carbonate quartz, Mineral assemblages of quartz–sericite and argillic altera vite (QSR I) phengite, QSR II Type of altered rockType Mineralogy bonate–muscovite ± bonate–muscovite Carbonate–quartz–illite Tourmaline–quartz–car Chlorite–quartz–musco Table 5. Rockforming constituents are bolded.

GEOLOGY OF ORE DEPOSITS Vol. 57 No. 3 2015 224 MARUSHCHENKO et al.

Al apfu 3.2 Muscovite I llite 2.8

2.4 P h en gi te 2.0

12345 67 89 1.6 3.0 3.2 3.4 3.6 Si apfu

Fig. 5. An Al versus Si plot for white micas from altered rocks of various deposits modified after CarrilloRosúa et al. (2009). (1– 4) Peschanka deposit and Nakhodka ore field: (1) muscovite of QSR I, (2) phengite of QSR I, (3) muscovite of QSR II, (4) pheng ite of QSR II; (5) illite of argillic rock; (6) muscovite of quartz–sericite rocks of CuMoporphyry deposits Yerington and Butte, US, Valley, Canada (Dilles et al., 2012), Erdenet, Mongolia, Zhireken, Aksug, and Sora, Russia (Sotnikov et al., 2002), Olkhovka, Russia (Rogacheva and Baksheev 2010); (7) muscovite from beresite of the Bestuybe, North Kazakhstan (Baksheev, 1996) and Berezovskii, Middle Urals (Baksheev and Kudryavtceva,1999) intrusionrelated gold deposits; (8) illite from argillic rock of Yerington and Butte porphyry copper deposits, US (Dilles et al., 2012); (9) illite from quartz–sericite rock of the Palai Islica Cu–Au volcanogenic deposit, Spain (CarrilloRosúa et al., 2009).

(а) Mg Mg Mg Mg

0.4 0.4

Fe Mn

Fe Mn Fe Mn Fe Mn Mg Mg (b)

1 5 2 6 Dolomite Dolomite 3 7 4

Ankerite Kutnohorite Kutnohorite Fe Mn Fe Mn

Fig. 6. Triangular diagrams in terms of Fe–Mg–Mn for dolomite group minerals. (a) Tourmaline–quartz–carbonate–muscovite ± phengite alteration of the Peschanka deposit and Nakhodka ore field, and beresite of intrusionrelated gold deposits; (b) argillic rock of the Nakhodka ore field and volcanogenic gold deposits. (1) QSR II of the Peschanka deposit; (2) QSR II of the Nakhodka ore field; (3, 4) beresite of intrusionrelated gold deposits: (3) Bestyube deposit, North Kazakhstan (Baksheev and Spiridonov, 1998), (4) deposit in Central (Generalov, 1990); (5) argillic rock of the Nakhodka ore field; (6, 7) volcanogenic gold deposits: (6) Zod, Armenia (Spiridonov, 1992), (7) Cavnic, Romania (Leroy et al., 2000).

GEOLOGY OF ORE DEPOSITS Vol. 57 No. 3 2015 QUARTZ–SERICITE AND ARGILLIC ALTERATIONS 225 improved this paper. This study was supported by the Generalov, M.E., Carbonates of gold deposit and formation Presidium of Russian Academy of Sciences (program conditions of carbonatebearing mineral assemblages, “Basic Research for Development of Zone of Vestn. Mosk. Univ., Ser. 4: Geol., 1990, no. 2, pp. 88–94. the Russian Federation”), Russian Foundation for Henry, D.J., Novák, M., Hawthorne, F., et al., Nomencla Basic Research (project no. 140531198a) and ture of the tourmalinesupergroup minerals, Am. Mineral., Baimka Mining Company LLC. 2011, vol. 96, pp. 895–913. Kaminskii, V.G., Comprehensive geological and prospect ing model of in the Baimka zone, REFERENCES Sov. Geol., 1989, no. 11, pp. 46–56. Kotova, M.S., Nagornaya, E.V., Anosova, M.O., et al., AlvaJimenez, T., Tosdal, R.M., Dipple, G., and Halley, S., Dating of metasomatic process and orebearing granitoids Variation in hydrothermal muscovite composition around of porhphyry copper prospects in the Nakhodka ore field, the Valley porphyry Cu–Mo deposit, Highland Valley dis Wsetrn Chukchi Peninsula, in: Mater. V Ros. konf. po izo trict, British Columbia, Canada, Proc. 11th SGA Biennial top. Geokhron (Proc. V Russ. Conf. Isotopic Geochron.), Meeting, Antofagasta: Univ. Catolica Norte, 2011, pp. 340– Moscow: Institute of Geochemistry and Analytical Chem 342. istry, Rusisan Academy of Sciences, 2012, pp. 181–184. Bailey, S.W., Summary of recommendations of AIPEA Leroy, J.L., Hube, D., and Marcoux, E., Episodic deposi nomenclature committee, Clay Miner., 1980, vol. 15, tion of Mn minerals in cockade breccia structures in three pp. 85–93. lowsulfidation epithermal deposits: a mineral stratigraphy Baksheev, I.A., Mineralogy, zoning, and formation condi and fluidinclusion approach, Can. Mineral., 2000, vol. 38, tions of plutonogenic gold–antimony deposits hosted in pp. 1125–1136. black shale: a case study of the Bestyube deposit, Northern MartínezSerrano, R.G. and Dubois, M., Chemical varia Kazakhstan, Extended Abstract of Cand. Sci. (Geolmin) Dis tions in chlorite at the los humeros geothermal system, sertation, Moscow: Moscow State University, 1996. , Clays Clay Miner., 1998, vol. 46, pp. 615–628. Baksheev, I.A. and Spiridonov, E.M., Carbonates of beresite Martynov, K.V., Equlibria of rocksforming carbonates and listvenite of the Bestyube deposit, Vest. Mosk. Univ., under hydrothermal conditions, Extended Abstract of Cand. Ser.4: Geol., 1998, no. 6, pp. 29–35. Sci. (Geolmin) Dissertation, Moscow: MSU, 1991. Baksheev, I.A. and Kudryavtseva, O.E., Carbonates and Migachev, I.F., Shishakov, V.B., Sapozhnikov, V.G., and white micas of beresite–listvenite as zoning indicators of Kaminskii, V.G., Ore and alteration zoning of porphyry the Berezovsky plutonogenic gold deposit, Midle Urals, in copper deposit in the Northeastern Russia, Geol. Rudn. Ural’skaya letnyaya mineralogicheskaya shkola99: Mater. Mestorozhd., 1984, vol. 26, no. 5, pp. 91–94. nauch. shkoly (Ural Summer Mineral. School99, Proc. Migachev, I.F. and Girfanov, M.M., Shishakov, V. B. The Sci. School), Yekaterinburg, 1999, pp. 294–300. Peschanka porphyry copper deposit, Rudy Met., 1995, no. 3, pp. 48–58. Baksheev, I.A., Nikolaev, Yu.N., Prokof’ev, V.Yu., et al., Porphyry–epithermal gold–molybdenum–copper system Nikolaev, Yu.N, Baksheev, I.A., Prokof’ev, V.Yu., et al., of the Baimka trend, Western Cukchi Peninsula, in Metal Precious metal mineralization of the Baimka trend, Western logeniya drevnikh i sovremennykh okeanov 2014: Mater. 20 Chukchi Peninsula: mineralogy, geochemistry, and fluid i nauch. mol. shkoly (Metallogeny of Ancient and Recent inclusions, Geol. Ore Deposits, (in press). 2104: Proc. 20th Sci. School), Miass: Institute of Rogacheva, L.I. and Baksheev, I.A., Mineralogy of metaso Mineralogy, Ural Branch, Russian Academy of Sciences, matic rocks and geochronology of the Olhovka porphyry 2014, pp. 108–112. copper deposit, Chukotka, Russia, 33rd Ann. General Meet. CarrilloRosúa, J., MoralesRuano, S., EstebanArispe, I., MDSG, Glasgow: Univ. Glasgow, 2010, pp. 39–40. and HachAlí, P.F., Significance of phyllosilicate mineral Shapovalov, B.C., Some geochemical features of ores in the ogy and mineral chemistry in an epithermal environment. Baimka cluster, in Rudnye formatsii SeveroVostoka SSSR insights from the PalaiIslica AuCu deposit (Almería, SE (Ore Types of Northeastern USSR), Magadan: SVKNII Spain), Clays Clay Miner., 2009, vol. 57, no. 1, pp. 1–24. DVO Akad. Nauk SSSR, 1990, pp. 162–170. Chitalin, A.F., Usenko, V.V., and Fomichev, E.V., The Sillitoe, R.H., Porphyry copper systems, Econ. Geol., 2010, Baimka ore zone – a cluster of large base and precious vol. 105, pp. 3–41. metal deposits in the western Chukotka AD, Mineral Res. Sotnikov, V.I., Berzina, A.T., and Berzina, A.P., Fluorine in Ross. Econ. Uprav., 2013, no. 6, pp. 68–73. white micas of Siberian and Mongolian porphyry copper– Corbett, G. and Leach, T.M., Southwest Pacific rim gold molybdenum deposits and its probable origin, Geochem. copper systems: structure, alteration and mineralization, Int., 2002, vol. 40, no. 10, pp. 1106–1114. Soc. Econ. Geol, 1998, Spec. publ., vol. 6. Spiridonov, E.M., Listvenite and zodite, Geol. Rudn. Mestorozhd., 1991, vol. 33, no. 2, pp. 38–48. Dilles, J.H., Footprints of porphyry Cu deposits: Vectors to the hydrothermal center using mineral mapping and litho Volchkov, A.G., Sokirkin, G.I., and Shishakov, V.F., Geol geochemistry. http://minerals.usgs.gov/mrerp/reports/ ogy and ores of the Anyui porphyry copper deposits, north DillesG10AP00052.pdf. Cited July 6, 2014. eastern USSR Geol. Rudn. Mestorozhd., 1982, no. 4, pp. 89–94. Le Fort, D., Hanley, J., and Guillong, M., Subepithermal Au–Pd mineralization associated with an alkalic porphyry Zharikov, V.A., Rusinov, V.L., Marakushev, A.A., et al., Cu–Au deposit, Mount Milligan, Quesnel terrane, British Metasomatizm i metasomaticheskie porody ( Columbia, Canada, Econ. Geol., 2011, vol. 106, pp. 781– and Metasomatic Rocks), Moscow: Nauchnyi mir, 1998. 808. Translated by I. Baksheev

GEOLOGY OF ORE DEPOSITS Vol. 57 No. 3 2015

View publication stats